A battery device mounted on a hybrid vehicle or an electric vehicle has a plurality of battery modules connected in series or in parallel. The plurality of battery modules are connected to each other by a bus bar. The battery module is provided with an electrode to be connected to the bus bar.
For the connection to the bus bar, a bolt is attached to a metal terminal of the electrode. The bolt attached to the metal terminal penetrates through the bus bar, and screw-fixed in a nut, so that the bus bar is firmly fixed.
Considering the process step of attaching the bus bar to the electrode, it is preferred to have the bolt temporarily fixed in advance on the metal terminal. As a method of such temporary fixing of the bolt, it may be possible to insert the bolt with pressure to a through hole provided in the metal terminal.
Japanese Patent Laying-Open No. 2002-8627 (Patent Document 1) discloses battery modules connected by such a bus bar. According to Patent Document 1, a plurality of cylindrical battery modules are connected by a plate-shaped bus bar.
Japanese Patent Laying-Open No. 7-226197 (Patent Document 2) discloses a battery for a portable electric device, having an easily bendable part with reduced width or thickness between an electrode plate and a connecting part of a relay lead.